![]() We can directly use the millis() function inside of a condition. ![]() Now an “if” statement has a condition and if the condition is true, then we execute the code in the “if” statement, but if the condition is false, then we skip that code. For example, let’s say we have an “if” statement. If you waited 7 days, the value “returned” would be 604,800,000 (7 days x 24 hours x 60 min x 60 secs x 1000 ms).Īnother way to get the value of millis() is to call the function inside of a condition. After 1 minute of being powered up, the variable will be equal to 60,000 (60 secs x 1000 ms). We see this when we print this variable to serial monitor. So every time the Arduino goes through its loop, this variable will be updated with the most recent count of time in milliseconds. Now let’s create a variable called “previousTime” and let’s set it equal to the output of the millis function. How do we use, or access, this time? We set the value that is returned to a variable. So in our case, when we “call” the millis function and it “returns” the current time in milliseconds that the Arduino has been running. When this function performs a calculation for you, and it gives you some information back, it’s said to “return” a value. When we type out millis() in our sketch, we’re “calling” the millis function. When you type a function out, as in when you use it in your code, you’re said to be “calling” the function, or another way, it’s said to be a “function call”. Let’s talk about two specific words, “call” and “return”. Let’s review some basic Arduino function jargon. To state it another way, the value that is returned by the function millis() is the amount of time that has passed since the Arduino board was powered up. When you call the millis() function, it returns the current value of the timer/counter in milliseconds (hence the millis() function name). To put it simply, the millis() function gives us access to the running tally that the timer/counter has been keeping track of. So how do we access this information? Enter the millis function. You may hear the jargon for when it reaches this maximum number and starts over as “rolling over”, but a more proper way to say it is the timer “overflows”. It will count until it reaches its maximum value, and then it starts again at zero. You don’t have to tell it to do this, it automatically starts on its own, and it never stops as long as there’s power applied. ![]() So the timer/counter starts counting “clock ticks” as soon as the Arduino powers up. Keep a running tally of the “clock ticks”.Count the “clock ticks” from the Crystal Oscillator.This module can do lots of things, but for our purposes, let’s just examine how it can: Thankfully the Arduino already has a module that counts these “ticks” for us, and it’s called a “timer/counter module” … go figure! So if we count how many “ticks” have occurred since the sketch has been running, we know how much time has passed since it was powered up. So what does “clock source” mean in this context? It means it’s generating a consistent signal, we can call this single a “tick” as in the “tick-tock” of old school analog clocks. The crystal oscillator is usually needed for things like serial communication in order to control the baud rate. The video above states this, but in reality, most Arduino use a ceramic resonator for time keeping. The integrated circuit that an Arduino uses has a built in hardware clock. Some are precise, some you can make yourself on a breadboard, and some are built into modulus that we can connect to our Arduino. There are a lot of different circuits that can generate voltage signals. Hang in there!Ī hardware clock is an electrical circuit that creates a signal (like a voltage pulse) at a consistent frequency. Specifically, let’s discuss what a “hardware clock” is and what a “timer counter” is. What is this millis() function anyway? Before we can explain this, we need some context. Doing multiple timed things with Arduino: Unleash the millis()!.delay Part 3 | A mini-series on Timing Events with Arduino Code delay() Arduino Function: Tight Loops and Blocking Code.What the tensile strength of a rubber band isĬheck out the entire series on using millis() here:.Doing math with unsigned longs (variables that are perfect for storing millis values).We will discuss this and more in the video tutorial below. Have you heard of the Arduino millis() function?ĭid you know that it gives you access to the Arduino internal timer counter hardware which can be used for the timing of different events?
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